In recent years, orientation toward low-price personal computers (hereinafter, abbreviated as “PC”) is becoming strong. In order to reduce the price of a PC, the prices of parts used in the PC are reduced, and the performance of the PC is reduced accordingly. For example, in low-price laptop personal computers (hereinafter, abbreviated as “laptop PC”), for example, a 1.6 GHz CPU which is far from a high speed CPU in recent years is used as a CPU (Central Processing Unit) which executes a program.
Here, it is assumed that a moving image content, which has 1280×720, 4:2:2 format and 30 frames and is a high-definition moving image content for distribution on the Internet, is reproduced. When the moving image content of this level is processed by, for example, a 2.2 GHz CPU, the CPU utilization is about 81%, and this is close to the limit in view of the entire system. When the moving image content is reproduced by a low-spec laptop PC as described above, the CPU utilization is about 111% by simple calculation in the case of a 1.6 GHz CPU. Thus, the CPU may not keep up with processing, and the moving image content is displayed with dropping frames, or a video image is not outputted but frozen.
In order to avoid occurrence of this defect, it has been proposed that a part of an inverse DCT process of an MPEG image data is skipped in accordance with a reproduction processing load and the load is suppressed, thereby reducing the possibility of dropping frames. However, in this case, when the load is reduced, the image resolution is reduced and a reproduced image may be blurred.
Moreover, it has been proposed that image data in multiple formats, such as YUV 4:2:4, YUV 4:2:2, and YUV 4:2:0, whose data volumes of color data are different from each other, are prepared, and, out of image data in these multiple formats, image data which is a target to be transformed to image data for display is changed for each one frame in accordance with a load. In this case, the color resolution of a video image may be reduced when the load is reduced, but the video image itself is reproduced with high resolution remained. However, in this case, it is necessary to prepare image data in multiple formats. Thus, this may cause an increase in communication traffic of the Internet or an increase in necessary storage capacity. In addition, for image data distributed on the Internet or the like, data in such multiple formats are not prepared in parallel (e.g., Japanese Unexamined Patent Application Publication No. 1999-146398 and Japanese Unexamined Patent Application Publication No. 2000-181438).